Known as a conventional spectroscopic sensor is one comprising a plurality of interference filter units for transmitting therethrough light having a predetermined wavelength according to an incident position of the light, a light-transmitting substrate for transmitting therethrough the light incident on the interference filter units, and a light detection substrate for detecting the light transmitted through the interference filter units. There is a case where each interference filter unit is constructed as that of Fabry-Perot type by making a pair of mirror layers oppose each other through a cavity layer.
As a method of manufacturing such a spectroscopic sensor, the following method is described in Patent Literature 1. A plurality of one mirror layers are initially formed on the light detection substrate, and then the cavity layer is formed on the mirror layers by nanoimprinting. A plurality of the other mirror layers are subsequently formed on the cavity layer, and the light-transmitting substrate is finally joined onto the mirror layers.